within reason, EVERY part of a DC07 is washable except the electricals etc.
Everything plastic can be washed, best not to wash the metal rods within the brushroll or the wheel axel though, the wand/handle will be fine. Bearings are also a big no-no so remove them if you are going to bath the brush.
Power cable, switch, motor etc obviously cannot be washed.
Wand/handle, hose all give a good soak.